Web Application Development Tutorial - Part 7: Authors: Database Integration

About This Tutorial

In this tutorial series, you will build an ABP based web application named Acme.BookStore. This application is used to manage a list of books and their authors. It is developed using the following technologies:

• MongoDB as the database provider.
• MAUI / Blazor Hybrid as the UI Framework.

This tutorial is organized as the following parts;

• Part 1: Creating the server side
• Part 2: The book list page
• Part 3: Creating, updating and deleting books
• Part 4: Integration tests
• Part 5: Authorization
• Part 6: Authors: Domain layer
• Part 7: Authors: Database Integration (this part)
• Part 8: Authors: Application Layer
• Part 9: Authors: User Interface
• Part 10: Book to Author Relation

Download the Source Code

This tutorial has multiple versions based on your UI and Database preferences. We've prepared a few combinations of the source code to be downloaded:

• MVC (Razor Pages) UI with EF Core
• Blazor UI with EF Core
• Angular UI with MongoDB

If you encounter the "filename too long" or "unzip" error on Windows, please see this guide.

Introduction

This part explains how to configure the database integration for the Author entity introduced in the previous part.

DB Context

Open the BookStoreMongoDbContext in the MongoDb folder of the Acme.BookStore.MongoDB project and add the following property to the class:

public IMongoCollection<Author> Authors => Collection<Author>();

Implementing the IAuthorRepository

Create a new class, named MongoDbAuthorRepository inside the Acme.BookStore.MongoDB project (in the Authors folder) and paste the following code:

using System;
using System.Linq;
using System.Linq.Dynamic.Core;
using System.Collections.Generic;
using System.Threading.Tasks;
using Acme.BookStore.MongoDB;
using MongoDB.Driver;
using MongoDB.Driver.Linq;
using Volo.Abp.Domain.Repositories.MongoDB;
using Volo.Abp.MongoDB;

namespace Acme.BookStore.Authors;

public class MongoDbAuthorRepository
    : MongoDbRepository<BookStoreMongoDbContext, Author, Guid>,
    IAuthorRepository
{
    public MongoDbAuthorRepository(
        IMongoDbContextProvider<BookStoreMongoDbContext> dbContextProvider
        ) : base(dbContextProvider)
    {
    }

    public async Task<Author?> FindByNameAsync(string name)
    {
        var queryable = await GetMongoQueryableAsync();
        return await queryable
            .FirstOrDefaultAsync(author => author.Name == name);
    }

    public async Task<List<Author>> GetListAsync(
        int skipCount,
        int maxResultCount,
        string sorting,
        string? filter = null)
    {
        var queryable = await GetMongoQueryableAsync();
        return await queryable
            .WhereIf<Author, IMongoQueryable<Author>>(
                !filter.IsNullOrWhiteSpace(),
                author => author.Name.Contains(filter!)
            )
            .OrderBy(sorting)
            .As<IMongoQueryable<Author>>()
            .Skip(skipCount)
            .Take(maxResultCount)
            .ToListAsync();
    }
}

• Inherited from the MongoDbRepository, so it inherits the standard repository method implementations.
• WhereIf is a shortcut extension method of the ABP Framework. It adds the Where condition only if the first condition meets (it filters by name, only if the filter was provided). You could do the same yourself, but these type of shortcut methods makes our life easier.
• sorting can be a string like Name, Name ASC or Name DESC. It is possible by using the System.Linq.Dynamic.Core NuGet package.

See the MongoDB Integration document for more information on the MongoDB based repositories.